Evans Prep Fluid is a waterless cooling system flush engineered specifically to purge the cooling system of water-based antifreeze after draining and before installing new Evans Power Sports coolant. Prep Fluid should be used when block drains are unavailable or cannot be removed. It is not a substitute for thoroughly draining the cooling system and related components. Prep Fluid is NOT intended to be a stand-alone operating coolant, but as a flush only.